The inventive concept described herein relates to memory devices, and more particularly, to a nonvolatile memory device and an operation method thereof.
Semiconductor memory devices are memory devices realized using a semiconductor such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP) and so on. Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices.
Volatile memory devices lose their stored data when their power supplies are interrupted. Volatile memory devices include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM) or the like. Nonvolatile memory devices maintain their stored data even when their power supplies are interrupted. Nonvolatile memory devices include a read only memory (ROM), a programmable ROM (PROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory device, a phase change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), and so on. A flash memory is classified into a NOR-type and a NAND-type.
As the integration of flash memory devices increases, a space between word lines is becoming narrow. As a result, an incorrect operation due to a coupling between word lines may occur. To reduce this coupling effect, a memory cell array of flash memory may include a dummy word line to widen a space between word lines. However, existing flash memory systems that include dummy word lines may still exhibit undesired coupling between the dummy word lines and actual word lines.